The present invention is related to an adaptive power supply module and, more particularly, to a module that is configured to adapt a fixed input power supply voltage to a predetermined level required to power a particular circuit or other arrangement.
Integrated circuit technology is constantly being advanced by a reduction in the size of the transistors used for circuit implementation, as well as the overall size of the circuit itself. One natural result of the reduction in transistor size is the concomitant reduction in the voltage level required to power the circuit. Not that many years ago, most integrated circuits would require a +/xe2x88x925V power supply. Many circuits today operate at +/xe2x88x923V, and newer circuits require as little as +/xe2x88x921.8V. Power supply voltages dropping below the 1V level is not out of the realm of possibilities.
When designing a complete circuit architecture at one time, the choice of power supply voltage can be handled and regulated through the circuit. That is, a fixed power supply (for example) can be utilized with any number or type of voltage regulator (e.g., a bandgap reference) to generate various desired supply voltage levels. However, there are many instances where a power-providing circuit, developed at one point in time, will need to be connected to a number of other circuits, developed over a period of years. In this case, the various power supply requirements of each separate module will become problematic. For example, a communications motherboard may have a plurality of N output ports available to accept a plurality of N separate transmit/receive modules. The transmit/receive modules may often times be re-developed over the course of time and, as a result, a later-developed module of the same xe2x80x9ctypexe2x80x9d may operate at a lower voltage than a predecessor design.
Thus, it would be desirable to provide an arrangement permitting modules of the same type, but operating at different reference voltages, to all be connected to and used with the same master circuit board.
The need remaining in the prior art is addressed by the present invention, which relates to an adaptive power supply module and, more particularly, to a module that is configured to adapt a fixed supply voltage to a, second, predetermined (different) level required to power a particular circuit or other arrangement. The module is utilized as an interface between the first, fixed supply voltage and the second, predetermined voltage input to the adjoining circuit. Each module may be individually configured to provide for the necessary correction between the fixed supply and the other circuit-required power supply.
In a preferred embodiment of the present invention, a fixed supply voltage source is used generate a predetermined reference voltage using, for example, a bandgap reference voltage generator. A resistor divider network and differential amplifier are used to form the adaptive power supply module and, in this case, reduce the generated reference voltage level to a predetermined lower (for example) level needed by the individual circuit. The fixed supply voltage is used to power the differential amplifier and the generated reference voltage is applied as a first input to the differential amplifier, where the resistor divider network is coupled to the amplifier output. The choice of the resistor values in the resistor divider network is used to control the actual output voltage, Vprog, and an internal node voltage in the resistor divider network is fed back to the difference input of the differential amplifier.
In one embodiment of the present invention, the resistor values may be adjusted during the lifetime of the circuit implementation to adjust for power supply changes as a function of time.
Other and further embodiments of the present invention will become apparent during the course of the following discussion and by reference to the accompanying drawings.